Titanium tetrachloride, which is a primary raw material of titanium, is produced by chlorinating reaction of titanium-containing raw material. This chlorinating reaction accompanies byproduction of chlorides of impurities such as iron, manganese, and magnesium contained in the titanium-containing raw material.
In addition, when titanium-containing raw material is consumed and becomes a fine powder during a chlorinating reaction using chlorine gas and coke in the chlorinating furnace, it may be carried to a next process while being unreacted, and it may be recovered as a solid component.
Furthermore, there may be carried and recovered oxides such as silicon oxide in titanium-containing raw material that is minimally chlorinated and is.
Furthermore, although the amount of byproduct is small if high titanium-containing raw material having large content of titanium is used, such high titanium-containing raw material is now becoming expensive with increasing worldwide demand for titanium and titanium alloys, and procurement thereof is becoming progressively difficult.
In view of such circumstances, a technique is required in which titanium-containing raw material that is available at a lower price than high titanium-containing raw material but which byproduces more impurities, is used really well.
In a case in which titanium-containing raw material is chlorinated, there is a tendency that the amount of solid recovered material generated during chlorinating reaction of titanium-containing raw material increases as the grade of the ore decreases.
Under these circumstances, important matters of attention are, in addition to the chlorinating reaction of ore itself, how the solid recovered material primarily containing chlorides of impurity components byproduced in the chlorinating reaction of ore is handled.
Furthermore, a method for treating recovered material that is unreacted and carried from a previous process is also identified as a similar subject.
The solid recovered material containing byproduct and carried-over recovered material during chlorinating reaction of titanium-containing raw material is conventionally treated being of the wet type, and then it is separated into solid and liquid components by treating by filter press. The solid component is treated as waste material. On the other hand, the liquid component is made harmless by a treatment such as neutralizing, and it is discharged as waste in the public sewer system.
The solid recovered material is not desirable from the viewpoint of environmental impact, and there is room for improvement from this viewpoint.
Regarding treatment of solid recovered material of titanium-containing raw material, for example, Japanese Unexamined Patent Application Publication No. 2005-015250 discloses a technique in which chlorides of impurity components byproduced together with titanium tetrachloride during chlorinating reaction of titanium-containing raw material is reacted with scrap titanium at a high temperature so that chlorine in the chlorides of impurity components is moved to titanium and thereby recovering titanium as titanium tetrachloride.
However, in this technique, although a method for recycling chlorides in solid recovered material is disclosed, there is no disclosure regarding treatment method of solid material contained in solid recovered material, such as fine powder titanium-containing raw material and coke which are unreacted carried-over recovered material, silicon oxide, and the like.
Furthermore, Japanese Unexamined Patent Application Publication No. Hei 02(1990)-026828 discloses a technique in which titanium oxide is separated from raw material discharged from a chlorinating furnace by electrostatic beneficiation so as to reuse it in the chlorinating furnace.
However, there is no disclosure regarding technique to recycle chlorides of impurity materials byproduced in chlorinating reaction of titanium-containing raw material or unreacted carried-over recovered material.
Furthermore, Japanese Unexamined Patent Application Publication No. Sho 52(1977)-114491 discloses a technique in which chlorine gas is reacted with a mixture comprising metallic chlorides and solid residue byproduced in chlorinating reaction of titanium-containing raw material so that ferrous chloride contained in the residue is converted into gaseous ferric chloride and chlorine gas is recovered by oxidizing and roasting the ferric chloride gas.
However, there is no disclosure regarding treatment method of solid residue including recovered, unreacted, carried-over material remaining after the reaction, and there is room for researching from the viewpoint of reducing environmental impact.
As is explained, a technique is required in which not only chlorine gas, but also unreacted titanium-containing raw material and coke contained in solid recovered material, can be effectively recycled from the solid recovered material generated during processes for production of titanium tetrachloride by chlorinating reaction of titanium-containing raw material.